On winding reconstruction method for six-phase motor with single-phase winding open-circuit faults

Single-phase winding fault in six-phase permanent magnet synchronous motor (PMSM) will cause problems with reduced torque performance. For this problem, this paper analyses the reasons for the increase of torque ripple under single-phase winding open-circuit fault condition taking an 18-slot/10-pole (18S10P) six-phase surface mounted permanent magnet synchronous motor (SPMSM) as an example. Then, a torque performance improvement method by redistributing healthy phase windings to reconstruct the stator magnetic field is proposed in this paper. The proposed method not only can significantly reduce torque ripple caused by winding open-circuit faults but also can maintain a high average torque value. Moreover, this method is suitable for lots of six-phase motors with different pole-slot combinations. At last, considering the significant impact of harmonic contents in stator magnetic field on torque performance, an optimization method for armature current is proposed, which can decrease the torque ripple further. The simulation results by finite element analysis (FEA) show that the proposed method has significant superiority in motor fault operation.